Heating of fluid



M. w. BARNES 2,292,682

HEATING OF FLUIDS Filed Feb. 10, 1941 INVENTOR MARION w. BARNES ATTORNEY Patented Aug. ll; 1942 HEATING F FLUID Marion W. Barnes, Chicago, 11]., assignor to Universal Oil Products Company, Chicago,

corporation of Delaware Application February 10, 1941, Serial No. 378,138

9 Claims.

- but is not limited to the treatment of any particular type of fluid.

The heater provided is-of the combination radiant and convection type and its structural form is similar to that disclosed in my United States Patent No. 2,212,002, issued August 20, 1940, the essential difference being in the formof fluid conduit provided and the flow of fluid therethrough. The heater provided by the present invention therefore retains the advantages of that disclosed in the aforementioned patent in so far as its general structural form is concerned and provides additional advantages in quickly heating fluids to relatively high temperatures with low pressuredrop through the fluid conduit. Quick heating and low pressure drop through the heating coil are often important factors, particularly in thermal or catalytic conversion reactions which are advantageously conducted at high temperatures and low pressure.

The accompanying drawing diagrammatically illustrates one specific form of theheater provided by the invention. Its advantageous feamay comprise two spaced refractory walls 8 and 9, which are preferably of suitable refractory shapes suspended from a suitable steel or other metal structure, not illustrated, disposed in space I0 provided between walls 8 and 9.

The fluid conduit or heating coil provided comprises a plurality of substantially parallel bent or U-shaped tubular elements II disposed adjacent' bridge wall 5 and each extending from a manifold or header I2 adjacent the floor of combustion and heating zone B to another manifold or header I3 disposed within fluid heating zone I adjacent the bridge wall.

Another portion of the fluid conduit is disposed substantially entirely within fluid heating zone I and comprises a plurality of substantially parallel tubular elements, each having a number of superimposed and interconnected U- shaped sections and each extending from a maid tures will be apparent from the following description. Its distinction from the heater disclosed in the aforementioned patent will also be apparent by reference to the latter and comparison of the structure illustrated and described therein with that herein disclosed.

In the drawing Fig. l is a diagrammatic sectional elevation of the heater and Fig. 2 is a diagrammatic section taken along the plane indicated by line 2--2 in Fig. l.

Referring to the drawing, the outer walls of the furnace comprise side walls I and 2, a roof 3, the interior surface of which is preferably curved, as illustrated, a floor 4 and end walls not illustrated in this particular view.

fold or header I5 which, in this instance,- is disposed outside the furnace structure adjacent the lower portion of wall 2 to the aforemen ioned manifold or headerl3 with which tubes I I are also connected.

As illustrated in Fig. 2, the U-shaped sections of each of the tubular elements I4 are disposed angularly with respect to the adjoining U-- shaped sections so that the horizontalstraight sections 6f tubes in each horizontal row of the bank comprising tubes: I 4 are disposed in staggered relation to those in the adjacent horizontal row. the combustion gases passing through zone 'I with the tubular elements I4, but is not to be construed as a limitation since the sections of each tube I4 may, when desired, be arranged in the same vertical plane.

Assuming that they flow of fluid undergoing through tubes II, it is supplied by any suitable well known means, not illustrated, through line The interior of the furnace is divided by bridge The bridge wall 5 may be built up solid of refractory shapes or, as in the case here illustrated,

I6 to manifold I5 and flows therefrom as a plurality of separate streams of substantially equal volume through tubular elements I4 in a general upward direction into manifold I-3. From manifold I3 the fluid flows as a plurality of separate streams of substantially equal volume through tubular elements I I, first in an upward direction through the portion thereof disposed in fluid heating zone I and then in a downward direction through that portion thereof disposed in combustion and heating zone 6, to manifold I2 wherefrom the heated fluid is discharged as a single stream through line I! to any desired destination. a

This arrangement gives better contact of' into combustion zone 6 through burner ports l8 by the jet action of the burner.

Although only a single burner and burner port are shown in this particular view of the furnace, a plurality of each is preferably provided at intervals so spaced along the length of the furnace as to give a substantially continuous curtain of flame and hot combustion gases a short distance above the burner ports.

The opening through each burner port is preferably at a slight angle from the horizontal, as here illustrated, whereby the flames and hot combustion gases are caused to impinge on the refractory side wall I and flow upwardly thereover, whereby the wall is heated to a radiant condition and the hot gases are partially cooled by contact therewith.

Heat is transmitted from the refractory side wall I, as well as from the flames and incandescent gases to one side of each of the tubular elements II and to the refractory wall 9, which latter, in turn, reflects heat to the opposite side of each of the tubular elements ll.

After leaving combustion and heating zone 6, the hot combustion gases travel over wall and, due to their heated condition, the main stream of these gases is maintained in intimate contact with the surface of roof 3. The curvature of the roof maintains a relatively stream line flow of gases and helps to eliminate excessive localized cycling of the combustion gases (commonly termed parasitic circulation) in the upper portion of the furnace. The hot gases passing over the surface of roof 3 heat the same to a high temperature and radiant heat is transmitted therefrom as well as from the hot gases themtion is not limited to all of the specific details of construction above mentioned, since many modifications and minor departures therefrom,

selves to that portion of the tubular elements H I located adjacent the upper portion of the bridge wall, the latter also serving to reflect heat to the opposite side of each of these tubes.

Depending upon the firing conditions employed and particularly upon the proportion of excess air utilized, the combustion gases having passed over bridge wall 6 from combustion and heating zone 6 to fluid heating zone I will retain a variable amount of radiant energy which is transmitted from the gases and from the refractory side wall 2 of the furnace to one side of that portion of each of the tubular elements ll located in fluid heating zone I and to the adjacent surface of the bridge wall which, in turn, reflects heat to the adjacent side of these tubes.

The upper portions of each of the tubular elements l4 may, depending upon the firing conditions employed, also receive a considerable amount of radiant heat and these tubular elements l4 receive fluid heat along substantially their entire length from the combustion gases which pass downwardly about and in contact therewith. After their contact with the tubular elements I4, the resulting substantially cooled combustion gases are directed through flue 2| to stack 22 wherein draft is controlled by means of a suitable damper 23.

which are within the scope of its broader aspects, will be readily apparent to those familiar with the art. For example, headers or manifolds similar to manifold l3 may be interposed in tubes H as the upper end of the substantially straight sections thereof in zones 6 and I, whereby only relatively short bent tube sections will be required over the top of the bridge wall to connect the manifolds. On the other hand, tubular elements I and II may be joined by substituting bends connecting the same in place of manifold l3. Manifold l5 may be disposed within rather than exterior to heating zone I, when desired, or, when desired, manifold [2 may be disposed exterior to combustion and heating zone 6 instead of within this zone, as illustrated. Although, in the case here illustrated, tubes I l and M are of substantially the same cross-sectional area, they may differ in size, when desired, and the number of tubes ll employed does not necessarily correspond to the number of tubes ll. It is also entirely within the scope of the invention to pass the fluid being heated, first through tubes H and then through tubes l4, employing manifold [2 as the inlet headerand manifold l5 as the outlet header.

The invention also contemplates, when desired, providing a plurality of inlet and outlet lines communicating with the respective inlet and outlet headers to obtain better distribution of fluid through the individual parallel sections of the fluid conduit and, in such instances, when desired, the inlet and outlet manifolds may be divided by suitable partitions into a plurality of inlet and outlet compartments. In the latter case, any desired number of separate streams of different fluids may be separately heated and by varying the quantity of fuel and air supplied through the independent burners, different firing conditions may be employed in different horizontal sections of zone 6 in order to obtain independently controlled heating conditions for each type of fluid supplied to the heater; particularly 1. A heater for fluids comprising, in combination, refractory exterior walls defining a combustion chamber and a fluid heating chamber separated by a refractory interior wall, means for directing hot gases resulting from the combustion of fuel through the combustion chamber in contact with the surface of the exterior wall facin said interior wall and fromthe combustion chamber into and through the fluid heating chamber, a fluid conduit comprising a plurality of tubular elements connected for substantially horizontal parallel flow of separate streams of fluid therethrough disposed in the direct path of travel of the combustion gases passing through said fluid heating chamber, and another fluid conduit comprising a plurality of tubular elements connected 2. A heater for fluids comprising, in gombina tion, refractory exterior walls definingr'aj combustion chamber and a fluid heating chambersepa rated by a refractory interior wall, means for aaoaelsa rate streams of fluid therethrough disposed in athe direct path of travel of the combustion gases ifiass'mg through the fluid heating chamber, and a plurality of tubular fluid conduits connected for directing hot gases resulting from the-combustion of fuel through the combustion chamber in.

contact with the surface of the exterior wall facing said interior wall and from the combustion chamber into and through the fluid heating chamber, a fluid conduit comprising a plurality: of I tubular elements connected for substantially horizontal parallel flow of separate streams 'of fluid therethrough disposed in the-direct; 'path of travel of the combustion gases passing through said fluid heating chamber, and anbther fluid conduit comprising a plurality of tubular elements connected for substantially vertical parallel flow of separate streams of fluid therethrough and disposed in the combustion chamber adjacent the surface of said interior wall, the first and second named conduits being connected for the flow of fluid therethrough in series.

3. The heater defined in claim 1, having its partsso arranged and constructed that said hot gases pass in a general vertical direction through the combustion chamber and through the fluid heating chamber with reverse flow in each of 30 said chambers'as compared with the other.

4. The heater defined in claim 2, having its parts so arranged and constructed that the fluid undergoing heating passes through said fluid conduits in a general direction countercurrent to that of the combustion gases from which they receive heat.

5. The heater defined in claim 2, having its parts so arranged and constructed that the fluid undergoing heating passes through said fluid conduits in a general direction concurrent to that of the combustion gases from which they receive heat.

6. A heater for fluids comprising, in combination, refractory side walls, end walls, a roof and a floor, a refractory bridge wall within the heater extending betweensaid end walls from the floor to a level substantially beneath the roof and dividing the interior of the heater into a combustion chamber and a fluid heating chamber, means for directing fuel and air upwardly into the combustion chamber toward the surface of the refractory side wall thereof facing said central wall, means for directing hotcombustion gases resulting from the combustion of said fuel upwardly through the combustion zone in contact with said side wall and over the central wall in contact with the roof into and through the the parallel flow of separate streams of fluid therethrough disposed adjacent the bridge wall and extending from adjacent the float in the combustion chamber over the bridge wall into the fluid heating chamber, the first and last named conduits being connected for the flow of fluid therethrough in series.

7. The heater defined in claim 6, wherein each of said tubular fluid conduits in the fluid heating zone comprises a plurality of substantially parallel straight sections connected in series by return bends, each of said conduits being'connected at one end with a common manifold and these conduits communicating at their opposite ends with the conduits adjacent the bridge wall.

8 The heater defined in. claim 6, wherein each of said tubular fluid conduits disposed adjacent the bridge wall comprises substantially vertical straight sections disposed on opposite sides of the bridge wall and connected over the top of the 9. A heater for fluids comprising, in combination, refractory side walls, end walls, an arched "roof and a floor, a refractory bridge wall within the heater extending betweensaid end 'walls from the floor to a level substantialy beneath the roof and dividing the interior of the heater into a combustion chamber and a fluid heating chamber, means for directing a combustible fuel air mixture into the combustion compartment toward the surface of the refractory side wall thereof facing the bridge wall, means for directing resulting hot combustion gases upwardly through the combustion chamber in contact with said side wall and over the bridge wall in contact with said arched roof into and through the fluid heating chamber, a plurality of tubular fluid conduits connectedfor the parallel flow of separate streams of fluid therethrough disposed in the direct path of travel of the combustion gases passing through the fluid heating chamber, each of said conduits beingsubstantially vertically disposed and comprising a plurality of substantially fluid heating chamber, a plurality'of tubular fluid horizontal sections connected in series by return bends, and a plurality of tubular fluid conduits connected for the parallel flow of separate streams of fluid therethrough and disposed adjacent the bridge wall, each of the last named conduits extending from adjacent the floor in the combustion chamber over the bridge wall into the fluid heating chamber, the first and last namedconduits being connected for the flow of fluid therethrough in series.

MARION w. BARNES. 

